Plane or axisymmetric state
2D Multi-scale Coupled Analysis:
Water-Air-Pollutant.
Type: 284
The element is defined by 4 or 8 nodes indicated in NODES according to the order presented in the Figure. 4 integration points are used for the interpolation.
Remark: the convergence is better with 4 nodes than with 8 due to numerical oscillations.
The mechanical constitutive laws that can be used with this element are, for instance:
Implemented by: A. Fanara based on the work of F. Bertrand, 2020
Prepro: EHYPOFE2A.F
Lagamine: EHYPOFE2B.F
Title (A5) | |
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TITLE | “EHYPO” |
Control data (2I5) | |
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NELEM | Number of elements |
INSIG | = 0 → No initial stress = 1 or 2 → Initial stresses |
Initial stresses - Only if INSIG > 0 (4G10.0) | |
If INSIG=1: $\sigma_y=\sigma_{y0}+yd\sigma_{y}$ If INSIG=2: $\sigma_y=min(\sigma_{y0}+yd\sigma_y,0)$ |
|
SIGY0 | $\sigma_{y0}$ effective stress $\sigma_y$ at the axes origin |
DSIGY | Effective stress gradient along Y axis |
AK0X | $k_0$ ratio $\sigma_x/\sigma_y$ |
AK0Z | $k_0$ ratio $\sigma_z/\sigma_y$ (if AK0Z=0, AK0Z=AK0X) |
The computation of SIGY0 and DSIGY must take into account the apparent specific mass, defined as \[\rho_a'=[(1-n)\rho_s+nS_w\rho_w]-\rho_w\] where: $\rho_s$ is the solid specific mass - this represents the specific mass of a fictive sample where ther is no porosity, i.e. where the grains occupy the whole volume of the sample $\rho_w$ is the fluid specific mass $n$ is the porosity defined in the flow law related to the element $S_w$ fluid saturation, ∈ [0,1] |
Definition of the elements (6I5/4 or 8I5) | |
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NNODM | Number of nodes for the mechanical description: 4 or 8 (preferred 4) |
NINTM | Number of integration point for the mechanical description: 4 |
LMATM | Mechanical law |
NNODP | Number of nodes for the fluid description: 4 or 8 (preferred 4) |
NINTP | Number of integration points for the flow description: 4 Must be equal to NINTM |
LMATF | Flow law |
NODES(NNODEM) | List of nodes |
Definition of the elements in the microstructure | |
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Line 1 (1I5) | |
NUMEL2 | Total number of micro-elements |
Line 2→NUMEL2+1 (6I5) | |
IELEM2 | Number of the micro-element |
ILAW | Type of element: 1=bedding plane, 2=bundle of tubes, 3=bridging plane |
NDUN | No. of the micro-node at corner 1 of the micro-element |
NDDEUX | No. of the micro-node at corner 2 of the micro-element |
NDTROIS | No. of the micro-node at corner 3 of the micro-element |
NDQUTR | No. of the micro-node at corner 4 of the micro-element |